Snap-action switch



June 19, 1945. r OBSZARNY 2,378,784

SNAP-ACTION SWITCH Filed March l5, 1943 2 Sheets-Sheet l Jiffy/a 'azzlllllllllllllirllAf-m June 19, 1945. T. oBszARNY 2,378,784

SNAP-ACTION SWITCH Filed March 15, 1943 2 Sheets-Sheet 2 Patented June19, 1945 UNITED 'STATES PATENT lOFFICE SNAP-ACTION swrrca ThedoreObszarny, Chicago, Ill., assigner to Guardian Electric ManufacturingCo., Chicago, lll., a corporation of Illinois application March 15,194s, serial No. 479,180

z claims. (ci. zoo-.61)

This invention relates to electrical switches a cooperating resilientactuating member, and of the snap-action type, -adapted for rapidlywherein one of the members is formed with a making and breakingelectrical circuits. yoke portion disposed in surrounding relation toMore particularly my invention is directed to the free end portion ofthe other member, and snap-action switches of the blade type adapted 5wherein the free ends of said members are interfor controlling eithersingle or multiple circuits, connected by a coil spring toggle servingto norand wherein such switches are usually of a relamally urge the freeends of the members apart. tively small compact construction, requiringa The present invention is directed to improvereliively Small r lightforce to effect operation ments in snap switches of the type referred tothereof. Due to the construction and character 1o in the foregoingparagraph, and has for one of of operation of switches of this type asheretoits objects the provision of stop means for limitforemanufactured, they have necessarily been ing the movement of theactuating member relamade as precision devices, requiring relativelytive to `the contact member, in one direction, to small tolerances.preclude separation of the switch contacts.

Certain switches of this general type. now availl Another object is toprovide improved stop able, are manufactured to such precision that itmeans locatedyin a position so as to be directly has been founddesirable to perform certain operengaged by the Vactuating member forlimiting ations 0n Darts thereof after complete assembly movementrelative -to lthe movable contact memof the switch. Such operationsobviously inber in one direction.

crease cost of manufacture of the switch. More- A further object is .toprovide a novel form and over the switches of this general type nowavailarrangement cf stop means, which is in .the na- Bille Practically91,11, include e movable member ture of a cantilever member, positionedto be or element formed of a strip of spring metal directly engaged bythe actuating member for which is mifmuy deformeg 'to provide what islimiting i-ts movement in one direction and by known as a sensitive areato which area presvirtue of its construction, is adapted to permit Sureis applied @C produce mixing of the Contact a slight excessive amount ofmovement of the frying portion of the member with a snap actuatingmember, as a safety factor, in the event action. Another constructionoi' this general type utilizes a. strip of spring metal which isinitially lgttlerggttmg member moved through too bowed and held .in suchposition so that it func' 30 Other objects and advantages of myinvention tions as a tension member. Still another type i will beapparent from the following description utilizes a strip of spring metaldisposed m bowed taken in connection with the accompanying formationbetween the free ends of two relatively drawings m which: movableactuating members and contact mem- Figure 1 is a top plan View of aswitch em] dy bers of the switch. 35

ing the present invention. All of such switch structures above referredto Figure 2 is a side elevational view of the switch. are of somewhatlimited life` because of the tend Figure 3 is a vertical longitudinalsection ency of the strip of deformed or tensioned spring metal to crtamz a en;` i through the switch, taken substantially as indiys e t c an areas due to Ire cated on lines 3--3 of Figure 1, showing the switchquent flexing 'actuation thereof. 40 c Another objectionablecharacteristic lof a switch m another position of adjustment' of thelast-mentioned type, is that in the event Figure 4 is a transversesectional View 'through of excessive movement of the actuating memberthe Switch taken substantially as indicate@ on in one direction, thepressure between the switch unes 5 4 0f Figure 2- contacts is reduced,and in some instances may Figure 5 .is a fragmentary View' partly insec' even result in separation of the contacts. This non and Partly in,elevation through 'the Spring condition is highiy objectionableparticuIariy in toggle connection. and taken substantially as ciectricoicircuits where it is important that after indicated cn lines 5-5 cfFigure 2.

a contact is made, such contact be maintained Figure 6fis a top PlanView 0f a modified fOrm for a certain period of time. 60 of snap switch,embodying the present invention.

More specifically this invention is directed to Figure 7 is a sideelevational view of the modiimprovemen-ts in a switch of the typedisclosed iicd i0rm 0f my SWiiChin my copending application Serial No.465,332, Figure 8 is a .transverse sectional view through filed Novemberl2, 1942, wherein I employ an the switch taken substantially asindicated on elongated, resilient, movable contact member and lines8--8v of Figure 7.

Figure 9 is an end elevational view of the contact making and breakingend of the switch.

Referring now to the switch construction disclosed in Figures l to 5 ofthe drawings, it will be noted that said switch is of the so-calledstack type and includes a pair of superimposed, elongated, relativelyrigid spaced apart contact bars or fingers IU and II provided at theirouter ends with contact buttons I la and IIa respectively. The contactbars are rigidly mounted at their rear ends in insulated relation toeach other between a plurality of insulated blocks or waters I I.

Mounted between the contact bars III and II is a relatively resilient,elongated, movable contact switch member I5, provided at its free end,on opposite sides thereof, with contact buttons I5a and I 5b adapted tocooperate respectively with the contact buttons Ia and II a of thecontact bars I and II.` The movable contact mem.

ber I is mounted at its rear end in the stack of insulating blocks I l,in spaced insulated relation to the contact members I0 and II as seen inthe drawings.

An elongated stamped yoke member I8, of resilient metal, which may betermed the actuating member, is flxedly mounted at its rear end incontact with the rear end portion of the movable contact member I5, ininsulated relation to the contact bars I0 and II, and has its outer orfree end portion disposed in surrounding relation to the outer free endportion of the movable contact member. The relatively rigid contact.bars I0 and II and movable contact member I5 are provided at their rearends with laterally extending ears or lugs indicated at IIlc, IIc andI5c respectively, to which may be conveniently connected, as bysolderingl conductor wires of the electrical circuit to be controlled bythe switch.

As is conventional in switches of this general type, the insulatingblocks Il and switch elements, as well as the yoke member I8, are eachprovided with a pair of aligned apertures in which are snugly fittedtubular insulating sleeves I9. so as to positively insulate therelatively rigid contact bars I0 and I I, and the movable switch memberI5 from each other. To further rigidify the entire assembly, the stackof insulating blocks are capped, both at the top and bottom, by metalplates 20, and the total stack assembly is adapted to be secured to aconvenient mounting by means of screws or bolts as indicated at 2 I.

It will be noted that the opening Ia of the yoke of the actuating memberI5 is so dimensioned as to permit free relative movement of the free endportion of the movable contact member and actuating member relatively toeach other.

The extreme outer free end portion of the movable contact member I5 isprovided with a projection I5d, which is in the nature of a taperedtang, and the yoke member, at the adjacent inner edge of the opening, isprovided with a projection `ltd extending in the direction of theprojection I5d, and which likewise is in the form of a tapered tang. Themarginal edge portions of the respective members I5 and I8 immediatelyadjacent the respective projections serve as abutment shoulders,

The two members I5 and I8 are interconnected at their free outer ends bya toggle spring arrangement which includes a pair of flanged tubulareyelets 22 and 23 disposed in telescoping relation to each other, withtheir flanged ends surrounding the projections I5d and Ild of saidmembers, and seated against said abutment :,svavas shoulders. A coilspring 25 surrounds the telescoping eyelets and abuts against the innerface of the ilanges of the respective eyelets, tending to urge theeyelets apart, and likewise tending to 5 urge the free end portions ofthe respective members Il and I8 apart. as seen in Figures 2 and 3 ofthe drawings.

It will now be apparent that when force is initially applied to theouter end of the yoke member I5 for causing it to move from the positionseen in Figure 2 of the drawings to the position shown in Figure 3 ofthe drawings, only suiilcient movement is necessary to shift the yokemember I8 through and beyond the plane of the outer free end portion ofthe movable contact member I5, and as it passes beyond said plane, themovable contact member I5 moves, by virtue of the toggle springconnection, with a snap-action to separate the contact buttons I5a andIa and cause iirm contact engagement of the contact buttons I 5b andIIa. It will be observed that during such movement of the actuatingmember I8, the coil spring 25 is slightly compressed, until theactuating member IB approaches alignment with the ilexible movablecontact member I5, and as the free end of the actuating member passesover or beyond the plane of the free end portion c! said contact member,the force of the compressed spring is expended to move the contactmember I5 with a snap-action, to its opposite position o! adjustment.

The extreme outer end portion of the actuating end portion I8 isprovided with a plug 21 of insulating material, which is adapted to beengaged by any suitable element foi applying the force or pressure tothe actuating member for causing it to move from the position seen inFigure 2 of the drawings to the position seen in Figure 3 of thedrawings.

It is to be understood that in the construction disclosed, the actuatingmember I8, is so constructed that when pressure on the plug 21 isreleased, the switch parts automatically resume a position as seen inFigure 2 of the drawings. It is to be understood however that theactuating member I8 may be so constructed that the switch parts mayremain relatively stable in either of its two positions of adjustment asindicated in Figures 2 and 3 of the drawings, while still obtaining thesame substantial advantages of the snap-action employed.

It will be apparent that by reason of utilizing a pair of telescopingeyelets the coil spring 25 is at al1 times guided during its movementfrom one position of adjustment to the other, as illustrated in thedrawings, and precludes any lateral buckling of the spring during suchmovement. 'I'hus the full balanced pressure of the coil spring isutilized for effecting the snap-action movement of the movable contactmember I5. and also tends to maintain a uniform pressure between thecontact buttons of the movable contact member I5 and the respectivecontact bars III and I I.

Because of the possibility of movement of the actuating member, ineither direction, beyond what may be considered a proper or normalrange, I provide suitable stop means in the form of relatively rigidelongated strips of insulating material as indicated at l0, mountedagainst the undersurface of the respective contact bars I0 and I I andhaving their ends mounted in the stack assembly between the insulatingblocks Il so as to become a fixed part of the total assembly. As may beseen in the drawings, the insulating strips 30 are approximately of thesame width as the overall width of the actuating member Il and are thusengageable by 'said member for limiting the movement thereof in eitherdirection. as clearly seen in the drawings. The outer ends of theinsulating strips 38 are formed with arcuate notches l8l so as toprovide clearance around the contact buttons Ilia and ila respectively,to avoid possible interference with the making of proper contact withthe contact buttons lia and IIb of the movable contactmember.

It will be observed that if the actuating member I8 is moved through toogreat a range, there is a normal tendency for the eyelets 22 and 23 tobecome disengaged and render the switch inoperative. Further, suchexcessive movement decreases the pressure of the coil spring 25 and thusdecreases the eil'ective pressure between the contact buttons. It ishighly desired that the pressure between the contact buttons be oisuilicient quantity, in order to insure making of good electricalcontact. By virtue of the provision of the stop members 80, theactuating member is arrested at a proper position, at opposite ends of adesired operating range of movement, at which it is possible to obtainthe use oi' the full force of the coil spring 28 for maintaining thecontact buttons in ilrm engagement with each other. 'I'he stops alsoserve the purpose of eliminating the tendency to deform the actuatingmember I8, which may result by movement thereof through too great arange, and which would impair proper snap-action operation.

In the modified constructions illustrated in Figures 6 to 9 inclusive,there is employed an elongated base member of suitable insulatingmaterial, which serves as the mounting for the snapaction switch.Rigidly mounted at one end of the base 88 is a relatively flexibleelongated actuating member 88 and a relatively iiexible elongatedmovable contact member 31, the latter being formed as a yoke anddimensioned with respect to the actuating member 36 so as to permitrela-'- tive movement of the free end portions of the movable memberrelatively to each other. Said members are rigidly secured at one end,on said base by means ofA rivets 39. Mounted between the mounting endsof the respective members is a terminal plate 4| which includes anextension projecting around theadjacent end of the base and terminatingat the underside thereof in an ear 4in. l

'I'he outer or free end of the movable contact member l1, which is ofyoke formation, is provided at its opposite faces with contact buttons31a and I'lb, adapted to engage respectively with contact buttons 44aand 45a of a pair of contact strips 44 and 45, rigidly attached to theopposite end of the base 40, at the underside thereof, as clearly seenin the drawings. The lower ends of said strips terminate in ears 44h and45h. Said terminal ears 4ia, 44h and 45h are adapted to be connected,such as by soldering, to conductor wires for embodying the switch in anelectrical circuit.

'Ihe free ends of the actuating member 38 and movable contact member 31are provided with cooperating tangs or projections 36e and 81o and areinterconnected by a spring toggle of the same general construction andarrangement as described in connection with the structure shown inFigures 1 (to 5 inclusive of the drawings, and the action of the springtoggle is identical and it is therefore deemed unnecessary to againrepeat the construction and operation thereof, and the correspondingparts are accorded similar reference numerals, supplemented by theletter a.

In the' position of the switch parts as seen in Figure 7 of thedrawings, the resilient actuating member 38 is seated upon the head 48of an operating plunger pin 48, slidably guided in a suitable recessedaperture formed in the base 35. It will be apparent that when the outeror exposed end oi' the plunger 49 is depressed, the'head 48 impingingupon the ilexibie actuating member 36, moves the free end portionthereof through the opening of the yoke type movable contact member 81,and as it passes through and beyond the plane of the latter, the springtoggle arrangement operates with a snap-action to move the contactbutton 31a out of engagement with contact button 44a and causesengagement of the button 31h with the contact button 45a'. When pressureon the pin 49 is removed, the switch parts move with a snap-action tothe initial position as seen in Figure 7. l

In the position of the switch parts seen in Figure 7 of the drawings,the head 48 of the plunger pin serves as a stop i'or limiting theposition of the actuating member I8 in one direction. To limit themovement of said member in the other direction, -I provide a relativelyrigid cantilever stop BI, mounted at one end on top of the movablecontact member 3l, by means of the rivets 38. Thus the stop arrangementprovided herein serves to limit the range of movement of the actuatingmember 38, so as to utilize and obtain the maximum advantage of thespring pressure of the toggle connection forf insuring proper pressurebetween the cooperating contact buttons.

I `Although I have herein shown and described certain preferredembodiments of my invention, manifestly it is capable of furthermodication and rearrangement of parts without departing from the spiritand scope thereof. I do not. therefore, wish to be understood aslimiting this invention to the precise forms herein disclosed, except asit may be so limited in the appended claims. y

I claim as my invention:

1. A unitary, stack type, snap-action switch assembly comprising a pairof elongated, relatively rigid contact bars disposed in aligned, spacedapart relation, an elongated, resilient contact member movable into andout of engagement with said contact bars, an elongated, resilientactuating member, said members extending in alignment with said bars andrigidly connected at one end and the free end portion of one memberbeing formed as a yoke and disposed in surrounding relation to the freeend portion oi the other member, said contact bars being rigidlyconnected at one end in insulated relation to said rigidly connectedends of said members, the free end portions of said members beingprovided with projections extending toward each other, a spring toggleconnection including a coil spring mounted on said projections andurging the free ends of said members apart, whereby movement of theouter free end portion oi the actuating member through and beyond theplane of the free end of the movable contact member effects movement ofthe later with a snap-action into and out oi.' engagement with saidcontact bars, and stop means positioned to be engaged by said actuatingmember for limitingits movement in one direction, said stop meanscomprising a relatively rigid strip of insulating material seatedagainst the inner surface of one of said contact bars and rigidlyconnected at one end to the assembly of said bars and members.

2. A unitary, stack type, snap-action switch assembly comprising a pairof elongated, relatively rigid contact bars disposed in aligned, spacedapart relation, an elongated. resilient contact member movable into andout of engagement with said contact bars, an elongated. resilientactuating member, said members extending in alignment with said bars andrigidly connected at one end and the free end portion o! one memberbeing formed as a yoke and disposed in surrounding relation to the freeend portion of the other member, said contact bars being rigidlyconnected at one end in insulated relation to said rigidly connectedends o! said members, the free end portions of said members beingprovided with projections extending toward each other, a spring toggleconnection including a coil spring mounted on said proiections and m1-ing the tree ends o! said members apart, whereby movement o! the outerfree end portion of the actautins member through and beyond tbe piane oithe free end oi the movable contact member eilects movement o! thelatter with a snap-action into and out of engagement with said contactbars. and stop means positioned to be engaged by said actuating memberfor limiting its movement in both directions, said stop means eamprisinga pair of relatively rigid strips of insulating material seatedrespectively against the inner surfaces of said contact bars and rigidlyconnected at one end to the assembly of said bars and members.

'I'HEDORE QBBZARNY.

